CN107001216B

CN107001216B - Intermediates and methods for preparing sandalwood oil building blocks

Info

Publication number: CN107001216B
Application number: CN201580065325.0A
Authority: CN
Inventors: O·克诺普夫; F·方特尼
Original assignee: Firmenich SA
Current assignee: Firmenich SA
Priority date: 2014-12-02
Filing date: 2015-11-16
Publication date: 2020-12-01
Anticipated expiration: 2035-11-16
Also published as: US20170260477A1; IL252157B; BR112017011065A2; JP6654194B2; ES2709926T3; EP3227255B1; WO2016087179A1; CN107001216A; MX2017005960A; US9879203B2; JP2017536381A; EP3227255A1; IL252157A0

Abstract

The present invention relates to a process for the preparation of an oxidized terpene fraction, which proves to be particularly useful in the preparation of sandalwood oil building blocks.

Description

Intermediates and methods for preparing sandalwood oil building blocks

Technical Field

The present invention relates to the field of organic synthesis, and more specifically to a process for the preparation of oxidized terpene fractions, which proved to be particularly useful in the preparation of sandalwood oil building blocks.

Background

The oxidized terpene fraction (I) is a novel composition of matter and is a useful starting material for carrying out the preparation of sandalwood oil building blocks in a short and efficient manner.

Sandalwood oil is a well-known perfuming ingredient that occurs naturally and comprises a variety of sesquiterpene allyl alcohols. However, due to nature, it fluctuates in the quantity and quality of production, and therefore alternative production of synthetic or natural oils and of building blocks from which they are made or recombined are required.

Biotechnological methods have recently been reported for the production of related sesquiterpene oils (i.e. oils as defined below for sesquiterpene hydrocarbon fraction (II)) using host cells/microorganisms expressing recombinant santalene synthase (e.g. WO 2011/000026 or WO 2010/067309). However, these methods neither allow nor suggest how to convert the sesquiterpene oils into analogues of sandalwood oil or sandalwood oil building blocks (i.e. keeping the appropriate proportions of each component as close as possible to the natural oil while converting the olefins into allyl alcohols).

In fact, the terpene synthase can produce a fraction containing several sesquiterpene hydrocarbons (i.e. a mixture of various sesquiterpene hydrocarbons) instead of one pure sesquiterpene hydrocarbon. Now, each component of these sesquiterpene hydrocarbon fractions does have a significantly different chemical structure, has a different reaction rate, the possible chemoselectivity of the reactive groups (providing the chemical effect required to produce sandalwood oil analogs), or is a sandalwood oil building block, which is extremely challenging.

To our knowledge, the prior art reports a number of methods for chemically converting the relevant sesquiterpene hydrocarbons into useful intermediates, i.e. the aldehydes described in the oxidized terpene fraction (I) of the present invention, but such chemical action has never been carried out on pure sesquiterpene hydrocarbons. For example, one may cite:

chem.be., 1907 by Semmeler et al,40,3321: ozonolysis of α -santalene and β -santalene are reported herein, respectively, but the yields (not reported) are necessarily rather low in view of the high difficulty reported in recovering the "aldehyde";

j.c.s.,1935,309 by Bradfield et al: ozonolysis of pure α -santalene and β -santalene is reported herein and indicates that β -santalene produces a large amount of CH2O, indicating that the exomethylene (methylene) of β -santalene is also attached;

chim.acta,1981,64,25, Snowden et al: wherein the epi- β -santalene is oxidized to (I-a) by using OsO4, NaIO 4.

None of these processes suggest an industrial process for converting sesquiterpene hydrocarbon fractions into related sandalwood oil building blocks or as intermediates for the oxidized terpene fraction (I). Indeed, these prior art teachings have even discouraged working on a mixture of various sesquiterpene hydrocarbons.

To our knowledge, the prior art only reports a process for converting sesquiterpene hydrocarbon mixtures into the corresponding sandalwood oil analogues (US 4510319). However, this method uses a mixture that does not contain bergamotene, a very sensitive substrate, using reagents such as Ca (ClO)₂It is clearly not the most industrially suitable reagent since halogenated intermediates are produced.

It is an object of the present invention to provide a more industrial process for the preparation of sandalwood oil building blocks starting from related terpene mixtures.

Disclosure of Invention

The primary object of the present invention is a composition of matter which is an oxidized terpene fraction (I) comprising:

15-40% w/w of 3- ((1S,2R,4R) -2-methyl-3-methylenebicyclo [2.2.1] hept-2-yl) propanal of formula (I-A),

wherein bold and hatched lines indicate the absolute configuration, said compound (I-a) preferably has an e.e. of at least 80%, 90% or higher than 95%;

1 to 8% w/w of 3- ((1S,2S,4R) -2-methyl-3-methylenebicyclo [2.2.1] hept-2-yl) propanal of formula (I-B),

wherein the bold and hatched lines represent the absolute configuration, said compound (I-B) preferably having an e.e. of at least 80%, 90% or higher than 95%;

40-60% w/w of 3- ((1S,3R,4S) -2, 3-dimethyltricyclo [ 2.2.1.0) of formula (I-C)^2,6]Hept-3-yl) propanal,

wherein the bold and hatched lines represent the absolute configuration, said compound (I-C) preferably having an e.e. of at least 80%, 90% or higher than 95%; and

5 to 20% w/w of 3- ((1S,5S,6R) -2, 6-dimethylbicyclo [3.1.1] hept-2-en-6-yl) propanal of formula (I-D),

wherein bold and hatched lines indicate the absolute configuration, said compound (I-D) preferably has an e.e. of at least 80%, 90% or higher than 95%;

the w/w ratio is relative to the total weight of the oxidized terpene fraction (I).

For the sake of clarity, the skilled person understands that the sum of the amounts of compounds (I-a) to (I-D) is at most 100% and at least 65% (obtained by said minimum amounts), if the sum is below 100%, the balance may be constituted by other compounds preferably derived from the oxidation of other natural sesquiterpene hydrocarbons, such as farnesene, curcumene, bisabolene, alpha-pinene, camphene and/or limonene (see for example below for the source of the raw material for preparing such oxidized terpene fraction). According to a particular embodiment, the compounds (I-a) to (I-D) do represent at least 80%, 85%, 90%, 95% w/w relative to the total weight of the oxidized terpene fraction.

For the sake of clarity, the skilled person understands that the expression "e.e" has the meaning of the art, i.e. "enantiomeric excess".

Another object of the invention includes an original process for producing an oxidized terpene fraction by oxidation of a sesquiterpene hydrocarbon fraction, preferably by fermentation preparation using a santalene terpene synthase, as well as the use of the oxidized terpene fraction for the preparation of sandalwood oil building blocks.

In view of the above, it can be easily seen that compound (I-A) is a precursor of (-) - (Z) - β -santalol, (I-B) is a precursor of (-) - (Z) -epi- β -santalol, (I-C) is a precursor of (+) - (Z) - α -santalol, and (I-D) is a precursor of (Z) - α -trans bergamotol. Thus, the present process represents the advantage of providing an oil which already comprises all the main components of the natural oil once, in contrast to all prior art processes and intermediates which may allow to produce only one or at most 2 of said components at once.

According to a particular embodiment of the invention, the oxidized terpene fraction (I) comprises:

20-35% w/w of a compound of formula (I-A);

1-5% w/w of a compound of formula (I-B);

40-55% w/w of a compound of formula (I-C); and

10-20% w/w of a compound of formula (I-D).

According to any of the above embodiments of the invention, the oxidized terpene fraction (I) is characterized by a w/w% ratio (I-C)/(I-D) of 4/1 to 2/1 (e.g. 50%/13% to 30%/15%).

According to any of the above embodiments of the invention, the oxidized terpene fraction (I) is characterized by a w/w% ratio (I-C)/(I-a) of 3/1 to 1/1 (e.g. 60%/20% to 30%/30%).

The oxidized terpene fraction (I) may advantageously be prepared by a process comprising the steps of:

reacting a sesquiterpene hydrocarbon fraction (II) with ozone under reducing conditions, the sesquiterpene hydrocarbon fraction (II) comprising:

i) 10-30% w/w of (1S,2R,4R) -2-methyl-3-methylidene-2- (4-methylpent-3-en-1-yl) bicyclo [2.2.1] heptane (also known as (-) - β -santalene) of formula (II-A),

wherein bold and hatched lines indicate the absolute configuration, said compound (II-a) preferably has an e.e. of at least 80%, 90% or 95%;

II) 1-6% w/w of (1S,2S,4R) -2-methyl-3-methylidene-2- (4-methylpent-3-en-1-yl) bicyclo [2.2.1] heptane (also known as (+) -epi- β -santalene) of formula (II-B),

wherein bold and hatched lines indicate the absolute configuration, said compound (II-B) preferably has an e.e. of at least 80%, 90% or 95%;

iii)20 to 50% w/w of (2S,4S,7R) -1, 7-dimethyl-7- (4-methylpent-3-en-1-yl) tricyclo [2.2.1.0 ] of formula (II-C)^2,6]Heptane (also known as (+) - α -santalene),

wherein the bold and hatched lines indicate the absolute configuration, said compound (II-C) preferably having an e.e. of at least 80%, 90% or 95%; and

iv)20 to 40% w/w of (1S,5S,6R) -2, 6-dimethyl-6- (4-methylpent-3-en-1-yl) bicyclo [3.1.1] hept-2-ene (also known as (-) - α -trans bergamotene) of formula (II-D),

wherein bold and hatched lines indicate the absolute configuration, said compound (II-D) preferably has an e.e. of at least 80%, 90% or 95%;

the w/w ratio is relative to the total weight of the sesquiterpene hydrocarbon fraction (II).

According to any of the above embodiments of the invention, the sesquiterpene hydrocarbon fraction (II) comprises:

15-30% w/w of a compound of formula (II-A);

1-6% w/w of a compound of formula (II-B);

20-40% w/w of a compound of formula (II-C); and

20-40% w/w of a compound of formula (II-D).

According to any of the above embodiments of the invention, the sesquiterpene hydrocarbon fraction (II) is characterized by a w/w% ratio (II-C)/(II-D) of 2/1 to 1/2 (e.g. 40%/20% to 20%/40%).

According to any of the above embodiments of the invention, the sesquiterpene hydrocarbon fraction (II) is characterized by a w/w% ratio (II-C)/(II-a) of 3/1 to 1/1 (e.g. 60%/20% to 30%/30%).

For the sake of clarity, the skilled person understands that the sum of the amounts of compounds (II-a) to (II-D) is at most 100% and at least 65% (obtained by said minimum amounts), if the sum is below 100%, the balance may consist of other terpene compounds, such as farnesene, curcumene, bisabolene, α -pinene, camphene and/or limonene (see for example below for the source of the sesquiterpene hydrocarbon fraction). According to a specific embodiment, the compounds (II-a) to (II-D) do represent at least 80%, 85%, 90%, 95% w/w with respect to the total weight of the sesquiterpene hydrocarbon fraction (II).

As described above, the substrate (II) is reacted with ozone (oxidizing agent). For the sake of clarity, by the expression "reducing conditions", the person skilled in the art understands that the intermediate trioxolane formed for obtaining the aldehyde is treated with at least one reducing agent, as is well known to the person skilled in the art. Such treatment with a reducing agent may be carried out at the time of post-treatment. As non-limiting examples of the reducing agent, the following can be cited: sulfites, e.g. alkaline sulfites (e.g. sodium or potassium sulfite, sodium bisulfite) or C_2-6Dialkyl sulfides such as dimethyl sulfide, triphenylphosphine, H₂And Pd/C, P (OMe)₃MeO (SO) OMe, MeSSMe, and the like. Mention may in particular be made of sulfites, such as alkaline sulfites (for example sodium or potassium sulfite, sodium bisulfite) or C_2-6Dialkyl sulfides, such as dimethyl sulfide.

The oxidation process may be carried out in the presence or absence of a solvent. When a solvent is required or used for practical reasons, any solvent in which the sesquiterpene hydrocarbon fraction is soluble and is currently used for oxidation or ozonolysis reactions may be used for the purposes of the present invention. Non-limiting examples include C_6-10Saturated hydrocarbon solvents, e.g. hexane or cyclohexane, saturated C_4-10Ethers or esters, e.g. AcOEt, tetrahydrofuran, dioxane or MTBE, saturated C_2-5Carboxylic acids, e.g. acids or propionic acids, saturated C_1-5Polar solvents, e.g. primary or secondary alcohols, e.g. isopropanol, methanol or ethanol, saturated C_2-6Ketones, e.g. butanone or isobutyl methyl ketone, C_1-3Chlorinated alkanes such as chloroform or dichloromethane, or mixtures thereof. The exact choice of solvent depends on the nature of the actual sesquiterpene hydrocarbon fraction and the desired reaction rate, and the skilled person will be able to select the most convenient solvent in each case to optimize the oxidation reaction.

The solvent may be added to the reaction medium in a wide range of concentrations. By way of non-limiting example, solvent amounts of 50% to 500% w/w with respect to the amount of sesquiterpene hydrocarbon fraction used may be cited.

The temperature at which the oxidation can be carried out is between-100 ℃ and 40 ℃, more preferably in the range of-80 ℃ to 0 ℃. Of course, the person skilled in the art will also be able to select the preferred temperature depending on the melting and boiling points of the starting and final products and the time required for the reaction or conversion.

The oxidizing agent, which is an essential parameter of the process, can be added to the reaction medium in a wide range of concentrations. As a non-limiting example, a concentration value of the oxidizing agent of 0.2 molar equivalents to 1.5 molar equivalents may be cited with respect to the amount of the sesquiterpene hydrocarbon fraction (II). Preferably, the oxidant concentration is 0.5 molar equivalents to 1.2 molar equivalents. It goes without saying that the optimum concentration of the oxidizing agent will depend on the nature of the latter, on the nature of the actual composition of the sesquiterpene hydrocarbon fraction, on the desired conversion and on the time required for the reaction, as known to the person skilled in the art.

The reducing agent, which is an essential parameter of the process, can be added to the reaction medium in a wide range of concentrations. As a non-limiting example, a concentration value of 0.2 to 3 molar equivalents of the reducing agent may be cited relative to the amount of the sesquiterpene hydrocarbon fraction (II). Preferably, the reducing agent concentration is 0.9 to 2.5 molar equivalents. It goes without saying that the optimum concentration of the reducing agent will depend on the nature of the latter, on the nature of the actual composition of the sesquiterpene hydrocarbon fraction, on the desired conversion and on the time required for the reaction, as known to the person skilled in the art.

The sesquiterpene hydrocarbon fraction (II) may be obtained by mixing together pure sesquiterpene hydrocarbons in the desired amounts, or more interestingly it may be obtained from a sesquiterpene hydrocarbon fraction produced by fermentation of host cells, such as microbial cells, which have been genetically engineered to convert an inexpensive carbon source, such as sugars, into the desired sesquiterpene hydrocarbon fraction by using (+) - α -santalene/(-) - β -santalene, as described in WO 2011/000026 or WO 2010/067309. The advantage of using the sesquiterpene hydrocarbon fraction (II) obtained by fermentation is evident, since this allows easy access to the starting material.

According to any of the above embodiments of the process of the invention, the process is further characterized in that the sesquiterpene hydrocarbon fraction (II) is obtained in a previous step in which a terpene synthase (known in the art) is contacted with farnesyl diphosphate (FPP) to produce the sesquiterpene hydrocarbon fraction (II).

The oxidation process of the present invention very surprisingly provides the following advantages:

excellent yields of compounds (I-A) to (I-C) while maintaining the initial w/w ratio of (I-A) to (I-C),

-allowing to reduce only the amount of compound (I-D) present in the final product with respect to the amount of (II-D) present in the sesquiterpene hydrocarbon fraction, thereby modulating the (Z) - α -trans bergamotol present in the final sandalwood oil building block.

These are important advantages, since in the preparation of sesquiterpene hydrocarbon fractions for the recombinant expression of santalene synthases in microorganisms, prior art data show that (-) - α -trans bergamotene is usually produced in amounts exceeding (Z) - α -trans bergamotol (usually found in natural sandalwood oil), which is clearly unsuitable. Thus, the present process allows for greater flexibility in the criteria for sesquiterpene hydrocarbon fraction production.

Further, as described above, although (I-A) and (I-B) do have other double bonds that can be oxidized to lower the yield, the yields provided for (I-A) to (I-C) are excellent.

Another aspect of the invention relates to the use of the oxidized terpene fraction (I) as starting material for the preparation of sandalwood oil building blocks. In fact, the main product in natural sandalwood oil is (+) - (Z) -alpha-santalol ((2S,4S,7R) - (Z) -5- (2, 3-dimethyl tricyclo [2.2.1.0 ]^2,6]Hept-3-yl) -2-methylpent-2-en-1-ol, (-) - (Z) - β -santalol ((1S,2R,4R) - (2Z) -2-methyl-5- [ 2-methyl-3-methylidene-bicyclo [ 2.2.1)]Hept-2-yl]Pent-2-en-1-ol, (-) - (Z) -epi-beta-santalol ((1S,2S,4R) - (2Z) -2-methyl-5- [ 2-methyl-3-methylidene-bicyclo [ 2.2.1)]Hept-2-yl]Pent-2-en-1-ol), (Z) - α -trans bergamotol ((2S,4S,7R) - (Z) -5- (2, 6-dimethylbicyclo [ 3.1.1)]Hept-2-en-6-yl) -2-methylpent-2-en-1-ol), it is therefore possible to obtain all the products directly from the components of the oxidised terpene fraction (I).

For clarity, "sandalwood oil structural unit" refers to a composition of matter comprising:

a) 20-35% w/w, preferably 20-30% w/w, (-) - (Z) - β -santalol

b) 1-8% w/w, preferably 2-6% w/w, (-) - (Z) -epi- β -santalol

c) 40-80% w/w, preferably 45-65% w/w, (+) - (Z) - α -santalol, and

d) 3-25% w/w, preferably 5-20% w/w, (Z) -alpha-trans bergamot oil alcohol.

The w/w ratio is relative to the total weight of the sandalwood oil structural units.

According to any of the preceding embodiments of the method of the invention, the sandalwood oil structural unit is characterized in that:

-w/w% ratio (+) - (Z) - α -santalol/(Z) - α -trans bergamotol is 10/1 to 3/1 or even 5/1 (e.g. 60%/6% to 50%/10%); and/or

The-w/w% ratio (+) - (Z) - α -santalol/(-) - (Z) - β -santalol is 3/1 to 3/2 (e.g. 60%/30% to 30%/20%).

For the sake of clarity, the skilled person understands that the sum of the amounts of components a) to d) is at most 100% and at least 64% (obtained by said minimum amounts), if the sum is below 100%, the balance may be constituted by other compounds preferably derived from other natural terpenes. The variation in the amounts of the various components a) to d) is due to the variation observed in natural oils, which depends on the plant species used for the production of the oil and the growth conditions (e.g. weather).

This composition of matter is considered to be a building block because it can be used to formulate sandalwood oil reformulations by adding additional perfume ingredients, as is common knowledge in the perfumery industry. However, it is also understood that the structural units can also be used as such to impart sandalwood-type odor notes.

The conversion of the oxidized terpene fraction (I) into sandalwood oil building blocks may be carried out using any suitable method known in the art, for example the method described in EP 10213 and/or WO 08/120175.

For the sake of clarity, the oxidized terpene fraction (I) is also referred to as "of the formula R-CH₂A composition of matter "of CHO, wherein R represents a group of formula:

and the expression "composition of matter" means we mean a composition of four possible compounds in the w/w ratio shown in the above-mentioned oxidized terpene fraction (I). Similarly, when further referred to as "composition of matter of formula R-, it is again meant to be according to R-CH₂Four possible compounds of the composition of matter in w/w ratios as defined by CHO, the only difference being the CH that can be converted into the other₂A CHO group.

As a non-limiting example, the normally oxidized terpene fraction (I) may be converted into sandalwood oil building blocks by performing the following reaction:

a) will be of the formula R-CH₂Coupling (Aldol condensation) of the CHO oxidized terpene fraction (I) with propionaldehyde to give the aldehyde R-CH₂A composition of matter of CH ═ cmecho (iii);

b) reacting the aldehyde R-CH₂Conversion of a substance combination of CH-CMeCHO (III) into the dienol R-CH-CMe-CHOR¹(IV) the corresponding composition of matter, wherein R¹Is represented by C₁-C₃Alkyl, alkenyl or acyl radicals or C₃-C₈A silyl group;

c) the dienol R-CH-CMe-CHOR¹(IV) reduction of the composition of matter to the precursor R-CH₂CH＝CMe-CH₂OR¹(V) composition of matter, wherein R¹As defined in formula (V), the moiety CH₂CH＝CMe-CH₂OR¹(V) is in the form of any one of its stereoisomers or a mixture thereof; and

d) the precursor R-CH₂CH＝CMe-CH₂OR¹(V) conversion of the composition of matter to the precursor R-CH₂CH＝CMe-CH₂Composition of matter of OH (VI) (sandalwood oil building blocks), said fraction CH₂CH＝CMe-CH₂OH is in the form of any one of its stereoisomers or a mixture thereof.

For the sake of clarity, by the expression "said part" in the form of any one of its stereoisomers or mixtures thereof, of the compositions (V) or (VI), it is meant herein that the carbon-carbon double bond is in the form of an E or Z isomer or a mixture thereof. According to any one of the above embodiments of the invention, said compound (I) is a compound in the form of a mixture of E and Z isomers, the Z isomer constituting at least 85% w/w, even at least 95%, even at least 98% of said mixture.

The above process is also described in scheme 1.

Route 1: conversion of oxidized terpene fraction (I) to sandalwood oil building blocks

Steps a) to e) may be carried out according to standard methods well known to the skilled person.

For example, the following methods may be enumerated for each step:

step a) according to EP 10213;

step b) the reaction was carried out according to Simmons et al, helv.chim.acta,1988,71,1000；

step c) the procedure was performed according to j.org.chem.,1988,531227 (in which [1,4 ] of a dienol acetate derivative is reported]Hydrogenated) or according to WO 08/120175; and

step d) is a simple ester hydrolysis well known to the person skilled in the art.

Examples of such methods are provided in the examples below.

Detailed Description

Examples

In all embodiments, the invention will be further described in detail by the following examples, wherein abbreviations have the usual meaning in the art, temperatures are indicated in degrees Celsius (. degree. C.); NMR spectral data in CDCl using 400MHz or 125MHz machines, respectively₃Middle record¹H or¹³C, chemical shifts are expressed in ppm based on TMS and coupling constants J are expressed in Hz.

The sesquiterpene hydrocarbon fraction (II) comprises:

-about 19.5% w/w of a compound of formula (II-a);

-about 2.5% w/w of a compound of formula (II-B);

-about 33.4% w/w of a compound of formula (II-C)

-about 38.4% w/w of a compound of formula (II-D); and

-about 5% w/w of beta- (Z) -farnesene

(w/w% relative to the total weight of sesquiterpene hydrocarbon fraction (II)), obtained by using E.coli cells engineered from the heterologous mevalonate pathway to overproduce farnesyl diphosphate (FPP) and co-expressing a plant-derived terpene synthase. Genetic engineering and use of E.coli host cells has been described in WO 2013064411 or J.Am.chem.Soc.2012,134: 18900-18903. Briefly, expression plasmids were constructed which contained two operons consisting of genes encoding enzymes of the complete mevalonate biosynthetic pathway. The first synthetic operon consisting of E.coli acetoacetyl-CoA thiolase (atoB), Staphylococcus aureus HMG-CoA synthase (mvaS), Staphylococcus aureus HMG-CoA reductase (mvaA), and Saccharomyces cerevisiae FPP synthase (ERG20) genes was synthesized in vitro (DNA2.0, Menlo Park, CA, USA) and cloned into pACYCDuet-1 vector (Invitrogen), yielding pACYC-29258. A second operon containing mevalonate kinase (MvaK1), phosphomevalonate kinase (MvaK2), mevalonate diphosphate decarboxylase (MvaD), and isopentenyl diphosphate isomerase (idi) was amplified from genomic DNA of Streptococcus pneumoniae (ATCC BAA-334) and subcloned into the second multiple cloning site of pACYC-29258 providing plasmid pACYC-29258-. Thus, this plasmid contains genes encoding all the enzymes of the biosynthetic pathway from acetyl-CoA to FPP. Coli cells (BL21 Star)^TM(DE3), Invitrogen) was co-transformed with plasmids pACYC-29258-4506 and pETDuet-1(Invitrogen) derivatives pETDuet-SCH10-Tps8201-opt containing a codon-optimized version of the cDNA encoding Santalum album (Santalbum) (+) - α -santalene/(-) - β -santalene synthase for expression in E.coli (example 6 of WO 2010067309). Using the resulting recombinant cells high cell density by using fed-batch in a laboratory scale bioreactorThe terpene fractions required for culture production are described mainly in (J.Am.chem.Soc.2012,134: 18900-18903). The sesquiterpene fractions were purified from the fermentation broth using a downstream process based on liquid/liquid extraction and fractionation. The method produces>Fraction of 90% pure sesquiterpenes.

Example 1

Preparation of oxidized terpene fraction (I) -ozonolysis (oxonolysis)

In a 500mL ozone flask, a solution of 19.6g (95mmol) of the sesquiterpene hydrocarbon fraction (II) above in methylene chloride (200mL) was cooled at-78 ℃. Ozone (5.47g, 1.2eq) was ignited by the solution at-78 ℃. The solution was then purged with oxygen for 10 minutes and then with nitrogen for 15 minutes. The mixture was returned at 0 ℃ and a solution of sodium sulfite (24g, 2.0eq) in water (250mL) previously cooled to 0 ℃ was added. The mixture was stirred at 0 ℃ for 10 minutes and at room temperature for 30 minutes. After decantation, the layers were separated and the aqueous layer was washed with Et₂And (4) extracting. The organic layer was washed with water and then brine. The combined organic layers were washed with MgSO₄Dried and filtered. The solvent was removed under vacuum and the residue (yellow oil) was purified by flash chromatography (eluent cyclohexane/AcOEt) to give 8.9g (53% overall yield) of an oxidized terpene fraction (I) containing 26/3/49/15 w/w% of compounds (I-A)/(I-B)/(I-C)/(I-D), respectively.

Yield of Compound (I-A) calculated on the basis of (II-A): 71 percent of

Yield of Compound (I-C) calculated on the basis of (II-C): 75 percent of

Yield of Compound (I-D) calculated on the basis of (II-D): 21 percent of

Example 2

Preparation sandalwood oil constitutional unit

The oxidized terpene fraction (I) obtained in example 1 was transformed according to scheme 1 and WO 08/120175.

Alditol step a): propionaldehyde 3 molar equivalents, hexahydroazepinium benzoate (hexahydroazepinium)1.0M in water 0.4 equivalents, toluene, 110 ℃,4 hours; the yield is 74%

Dienol ester step b)：Ac₂O3 molar equivalent, Et₃N1 molar equivalent, Ac^OK0.22 molar equivalent, 120 ℃,4 hours; the yield is 84%

Reduction of the dienol step c): maleic acid 0.16 molar equivalent, RuCp (COD) BF₄0.01 molar equivalent of acetone, H₂4 bar, 60 ℃ for 4 hours

Hydrolysis step d)：K₂CO₃1.2 molar equivalents, MeOH, 1 hour at room temperature, 68% total yield for steps d) and c)

In the resulting final sandalwood oil building block, the proportions of the various sesquiterpene allyl alcohols correspond to the same proportions of the corresponding compounds in the oxidized terpene fraction (I) obtained in example 1.

Claims

1. A composition of matter which is an oxidized terpene fraction (I) comprising:

wherein bold and hatched lines indicate absolute configurations;

wherein bold and hatched lines indicate absolute configurations;

40-60% w/w of 3- ((1S,3R,4S) -2, 3-dimethyltricyclo [ 2.2.1.0) of formula (I-C)^2,6]Hept-3-yl) propanal，

Wherein bold and hatched lines indicate absolute configurations; and

wherein bold and hatched lines indicate absolute configurations;

2. A composition of matter according to claim 1, characterized in that it comprises:

20-35% w/w of a compound of formula (I-A);

1-5% w/w of a compound of formula (I-B);

40-55% w/w of a compound of formula (I-C); and

10-20% w/w of a compound of formula (I-D).

3. The composition of matter according to claim 1, wherein the composition of matter is characterized by comprising:

4/1 to 2/1 in a w/w% ratio of (I-C)/(I-D); and/or

3/1 to 1/1 in a w/w% ratio of (I-C)/(I-A).

4. The composition of matter of any one of claims 1-3, wherein the compounds (I-A), (I-B), (I-C), and (I-D) have an e.e. of at least 80%.

5. A process for preparing a composition of matter as defined in any one of claims 1 to 3, comprising the steps of:

wherein bold and hatched lines indicate absolute configurations;

wherein bold and hatched lines indicate absolute configurations;

wherein bold and hatched lines indicate absolute configurations; and

wherein bold and hatched lines indicate absolute configurations;

6. The process according to claim 5, wherein the sesquiterpene hydrocarbon fraction (II) is characterized in that it comprises:

2/1 to 1/2 in a w/w% ratio of (II-C)/(II-D); and/or

3/1 to 1/1 in a w/w% ratio of (II-C)/(II-A).

7. Process according to claim 5, characterized in that the reducing conditions are carried out by using alkaline sulfites or C_2-6Dialkyl sulfide treatment of the reaction medium.

8. Process according to claim 5, characterized in that the sesquiterpene hydrocarbon fraction (II) is obtained in a previous step in which a terpene synthase is contacted with farnesyl diphosphate (FPP) to produce the sesquiterpene hydrocarbon fraction (II).

9. Use of the oxidized terpene fraction (I) as defined in any of claims 1 to 4 as starting material for the preparation of sandalwood oil building blocks.

10. Use according to claim 9, characterized in that the sandalwood oil building block is a composition of matter comprising:

a) 20-35% w/w of (-) - (Z) -beta-santalol

b) 1-8% w/w (-) - (Z) -epi-beta-santalol

c) 40-80% w/w (+) - (Z) - α -santalol, and

d) 3-25% w/w of (Z) -alpha-trans bergamot oleyl alcohol.

11. Use according to claim 10, characterized in that the composition of matter comprises:

a) 20-30% w/w (-) - (Z) -beta-santalol

b) 2-6% w/w (-) - (Z) -epi-beta-santalol

c) 45-65% w/w (+) - (Z) - α -santalol, and

d) 5-20% w/w of (Z) -alpha-trans bergamot oleyl alcohol.